The present invention relates generally to MEMS gyroscopes, and more particularly, relates to utilizing a pulse width modulation drive signal for MEMS gyroscopes.
Microelectromechanical systems (MEMS) have the potential to transform a number of different industries in modern society. Ranging from aerospace to bioengineering, the impact of MEMS is likely to be as profound and pervasive as that of integrated circuits. In particular, the use of MEMS devices as sensors and actuators in electromechanical systems is very promising. By creating electrical and mechanical components on a silicon substrate using standard microfabrication techniques, MEMS technology enables relatively small, cheap, and accurate sensing devices to be created. MEMS sensors and actuators are already being used in numerous commercial devices, including automobile airbag accelerometers and vibration sensors.
A common application of MEMS sensors has also been in the use of gyroscopes, which may use the motion of a vibrating element to measure an angular rate of rotation. A variety of MEMS gyroscopes are commercially available, including tuning fork gyroscopes and angular rate sensing gyroscopes. In the case of tuning fork gyroscopes, three orthogonal axes (drive, input, and sense) may be utilized for describing gyroscope motion. When a tuning fork gyroscope is in operation, a vibrating element may be placed in oscillatory motion along the direction of the drive axis while the gyroscope rotates about the input axis. These motions may result in a Coriolis acceleration that can be measured along the direction of the sense axis. Using a well-known mathematical relationship, the angular rate of rotation of the gyroscope about the input axis may then be calculated.
Despite the advantages of MEMS technology, prior art MEMS gyroscopes often face a number of drawbacks. In prior art systems, amplitude modulated drive signals are often used for creating the oscillatory motion of the vibrating elements. Such drive signals may be susceptible to external interference and may become distorted during transmission. Additionally, complicated circuitry (e.g., complex Automatic Gain Control (AGC) loops and analog multiplier circuits) may be required for creating and maintaining such drive signals.
Accordingly, it is desirable to have a drive signal for a MEMS gyroscope that overcomes the above deficiencies associated with the prior art. This may be achieved by utilizing a pulse width modulation drive signal for improved performance of a MEMS gyroscope.
A system and method for measuring the rate of rotation of a MEMS gyroscope is provided. In an exemplary embodiment, a MEMS gyroscope may be coupled to drive electronics operable to provide a pulse width modulation drive signal to the MEMS gyroscope.